Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F110/00—Homopolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond

Definitions

• the present invention relates to a process for the polymerization of alpha-olefins, particularly ethylene, by means of a catalyst system constituted by an aluminum alkyl and the combination of a transition metal chloride and titanium trichloride finely dispersed on a material having a high superficial area; moreover it relates to the employed catalyst and also to the method of preparing such a catalyst.
• titanium halides active from a catalytic point of view, are employed in the low pressure polymerization of alpha-olefins, they being prepared by reducing titanium tetra-halides with aluminium alkyl or alkyl-halide compounds.
• the reaction is generally carried out under an inert atmosphere and in the presence of an inert solvent.
• the so obtained catalyst is then used together with metal alkyl compounds for the polymerization of alpha-olefins in suspension in an organic solvent under reasonable pressures of the monomer.
• titanium halides are impure because of the presence of aluminum compounds and do not show a very high catalytic activity so that the final polymer needs expensive washing operations in order to remove the catalytic residues.
• titanium halides are carried on inorganic substances so that polymerization catalysts are obtained having an improved effectiveness.
• carriers used are selected from magnesium oxide or hydroxide; however it is to be noted that the catalytic activity of the titanium compound, carried on these materials, undergoes substantial changes according to the chemical nature of the surface thereof; therefore such compounds, in many cases, must undergo treatments with Grignard reagents, aluminum alkyl compounds or hydrogen to improve their effectiveness.
• One object of the present invention is a process for the polymerization of alpha-olefins by means of a catalytic system which has a high activity and does not need any preliminary treatment of the carrier.
• This catalytic system which is a second subject of the present invention, is constituted by two components, i.e.:
• aluminum compound selected from the ones having the formula AlR 3 or AlR x Y 3 -x in which R is an alkyl, aryl or cycloalkyl radical, Y is a halogen or H, and x is a number comprised between 1 and 2, and
• a method which is a third aspect of the present invention, consisting in impregnating the carrier, previously dehydrated by a thermal treatment, with a low valence transition metal compound, particularly a zero valence one, preferably a carbonyl metal derivative, dissolved in a hydrocarbon solvent, and then in titanium tetrachloride and, finally in removing the excess of this latter from the carrier.
• a low valence transition metal compound particularly a zero valence one, preferably a carbonyl metal derivative
• the zero valence transition metal compound may contain ligands of a type different from the carbonyl one, for instance allyl, olefine, carbonic, nitrosyl groups, etc.
• p means the carbonyl number and n means the valence state taken by the transition metal M during its oxidation from titanium tetrachloride.
• the material used as carrier for the aforesaid reaction is selected from the rare earth oxides whereas the transition metal is preferably selected from V, Mn, Fe, Co and it is used in an amount ranging from 0.1 to 10% by weight with respect to the carrier weight, preferably from 1 to 3% by weight.
• the material, employed as carrier is selected from neodymium, lanthanum and cerium oxides, whose availability as is the case with other rare earth compounds, is increasing, they being obtainable, as by-products, from the titanium metallurgy and the nuclear reactors.
• pretreatments are not necessary since the activity of our catalytic systems is high and homogeneous, even if the chemical nature of the carrier undergoes changes; however such carriers can also be subjected to pretreatments with Grignard reagents or aluminum alkyl-halides so as to further increase the performances thereof.
• the polymerization reaction is carried out according to known procedures at temperatures in the range of from 0° to 200° C. and at pressures ranging from 0.1 to 50 atmospheres.
• the polymerization is carried out in a steel autoclave equipped with an anchor stirrer when the operations are carried out at pressures higher than the atmospheric one.
• the catalyst is introduced together with the solvent and the metal alkyl compound.
• the autoclave being thermostated at the polymerization temperature, H 2 and then ethylene are introduced therein under pressure at the desired pressure ratio.
• the reaction is stopped by adding alcohol to the autoclave.
• the solvent, the organic metal compound (in concentration equal to 0.2% by volume) and the transition element compounds association, previously prepared as specified, are introduced into the autoclave, thermostated at 85° C.
• the ethylene pressure is kept constant for the whole test which occupies over six hours.
• the procedures described in the following examples refer to these working conditions (standard polymerization).
• the obtained polymers are dried under vacuum to a constant weight before evaluating the yields as polymer.
• composition of the product was the following one

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=11271661

Family Applications (1)

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Citations (5)

• 1974
  • 1974-03-28 IT IT49831/74A patent/IT1004430B/it active
• 1975
  • 1975-03-06 ZA ZA00751388A patent/ZA751388B/xx unknown
  • 1975-03-18 YU YU0669/75A patent/YU36871B/xx unknown
  • 1975-03-24 NO NO751001A patent/NO146638C/no unknown
  • 1975-03-25 FR FR7509330A patent/FR2265769B1/fr not_active Expired
  • 1975-03-25 DK DK125875A patent/DK144795C/da not_active IP Right Cessation
  • 1975-03-26 CA CA223,382A patent/CA1057273A/en not_active Expired
  • 1975-03-26 LU LU72136A patent/LU72136A1/xx unknown
  • 1975-03-27 DE DE19752513926 patent/DE2513926A1/de not_active Ceased
  • 1975-03-27 US US05/562,800 patent/US4037041A/en not_active Expired - Lifetime
  • 1975-03-27 BE BE154832A patent/BE827258A/xx not_active IP Right Cessation
  • 1975-03-27 SU SU752116656A patent/SU828972A3/ru active
  • 1975-03-27 NL NLAANVRAGE7503783,A patent/NL173410C/xx not_active IP Right Cessation
  • 1975-03-27 SE SE7503638A patent/SE425495B/xx unknown
  • 1975-03-27 HU HU75SA00002770A patent/HU171956B/hu unknown
  • 1975-03-28 CS CS752153A patent/CS207559B2/cs unknown
  • 1975-03-28 JP JP50037007A patent/JPS5242198B2/ja not_active Expired
  • 1975-04-11 IL IL47075A patent/IL47075A/xx unknown
  • 1975-12-02 SU SU752193807A patent/SU665781A3/ru active

Patent Citations (5)

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